The present invention relates to an all-terrain bicycle having a four-piece frame and plastic molded wheels wherein the tires are provided with wings for the displacing the bicycle on soft surfaces such as sand, grass, etc.
All-terrain motorized vehicles are known and are very popular nowadays. Also, the conventional bicycle has been modified and equipped with special shock absorbers and modified tires whereby the rider can drive over irregular terrain and not be subjected to the shocks imparted by such irregular terrain. These are commonly referred to as xe2x80x9cmountain bikes.xe2x80x9d The wheels are still of the conventional construction whereby an inflatable tire is secured about the rims. However, these tires are larger in cross-section than the conventional touring bicycle and are provided with various types of thread formations to provide better surface engagement. These xe2x80x9cmountain bikesxe2x80x9d are popular for driving along rough trail surfaces such as mountain trails where the bicycle encounters irregular hard packed terrain encumbered with stones, branches, mud and other like obstacles. However, such bicycles are not practical for driving into very soft ground surfaces where there is no hard support for the tires and the tires will sink into the surface and cause the rider to fall.
Another disadvantage of bicycles is their tubular metal framework, wherein the bicycle frame is constructed from thin metal tubes. These tubes are usually circular in cross-section and are machined at their outer ends whereby to fit against another tubular frame and disposed at an angle thereto for welding. These frames are connected by welds formed along the arcuate faces of the framework, and these welds may be difficult to execute. These metal tubes are usually 20 to 22 mm in thickness, whereby the bicycle may be made as light as possible. The result of this is that the welds can puncture the metal and, when these bicycles are utilized as xe2x80x9cmountain bikes,xe2x80x9d they are subjected to abuse and often the framework will break at the welds. Furthermore, because there are many interconnecting parts in the framework, the manufacture of the bicycle is time-consuming.
It is a feature of the present invention to provide an all-terrain bicycle which is specifically adapted for riding on soft and irregular terrain surfaces such as sand, snow, grass or other like soft surfaces, and which can also be utilized on hard surfaces and difficult terrain.
Another feature of the present invention is to provide an all-terrain bicycle which is provided with an improved frame having fewer welds and wherein the welds are stronger than heretofore known bicycle frameworks.
Another feature of the present invention is to provide an all-terrain bicycle wherein the wheels of the bicycle are entirely molded of plastics material.
Another feature of the present invention is to provide an all-terrain bicycle which is easy to construct and which is very resistant to impact.
Another feature of the present invention is to provide an all-terrain bicycle wherein the frame of the bicycle is formed by only four shaped tubular parts welded together.
According to the above features, from a broad aspect, the present invention provides an all-terrain bicycle which is comprised of a bicycle tubular frame defined by a main frame section and a front fork and a pair of rear forks to which is removably secured a front and a rear wheel. The wheels are formed of plastics material and define a hub, a circular outer molded solid tire and an intermediate connecting framework. The outer molded solid tire is a one-piece tire defining, when viewed in transverse cross-section, a central projecting dome merging into opposed tapered wings which are recessed from the top of the dome. An integrally molded connecting formation extends under the dome and is secured to an outer rim of the connecting framework. The dome defines a circumferential central rib about the outer molded tire for the displacement of the bicycle on a hard surface, with the wings spaced from the hard surface. The wings constitute a wide tire support surface, together with the central rim, for the displacement of the bicycle on soft surfaces.